High-resolution optical encoder with phased-array photodetectors

• US 6,928,386 B2
• Filed: 03/18/2003
• Issued: 08/09/2005
• Est. Priority Date: 09/14/1999
• Status: Expired due to Term

• Current Assignee: Immersion Corporation
• Original Assignee: Immersion Corporation
• Inventors: Hasser, Christopher J.
• Primary Examiner(s): Barlow, John
• Assistant Examiner(s): VO, HIEN XUAN
• Application Number:
  US10/391,060
• Publication Number:
  US 20040061502A1
• Time in Patent Office: 875 Days
• Field of Search: 702/163, 702/159, 702/172, 250/214.1, 250/201.2, 250/201.5, 250/216, 250/221, 250/231.14, 250/200, 736/50, 736/49, 736/59, 359/197
• US Class Current: 702/163
• CPC Class Codes: G01D 5/34 the beams of light being detected by photocells
• CPC Class Codes: G01D 5/34715 Scale reading or illumination devices
• CPC Class Codes: G01D 5/3473 Circular or rotary encoders
• CPC Class Codes: G01D 5/366 Particular pulse shapes

Abstract

Embodiments of high-resolution optical encoders having phased-array photodetectors and integrated on semiconductor chips. Emitters, detectors, and encoders disks are described which can be easily produced with semiconductor processes, such as a detector array provided with lens to collimate light and enhance detection. Integrated sensor chips include an array of photodetectors that receive energy from a beam emitted from an emitter and modulated by an encoder disk, analog-to-digital converters, state machines, counters, a communication module, a sensor processing unit, and a force computation unit. One embodiment includes low resolution and high resolution modes and an emitter controlled by sensor circuitry. A detector for an optical encoder can be provided on a single chip that includes a first array of photodetectors used for absolute sensing of a moving object, and a second array of photodetectors used for incremental sensing of the moving object.

Claims

1. An apparatus comprising:

at least two first photodetectors and at least two second photodetectors, the first and second photo detectors forming a first channel of a photodetector array, the first photodetectors linked together and the second photodetectors linked together, one of the first photodetectors adjacent to at least one of the second photodetectors; and

at least two third photodetectors and at least two fourth photodetectors, the third and fourth photodetectors forming a second channel of the photodetector array, the third photodetectors linked together and the fourth photodetectors linked together, one of the third photodetectors adjacent to at least one of the fourth photodetectors, the second channel offset from and out of phase with the first channel.

2. The apparatus of claim 1, wherein the second channel is approximately 30 degrees out of phase with the first channel.

3. The apparatus of claim 1, wherein the first and second channels are disposed on a semiconductor integrated circuit chip.

4. The apparatus of claim 1, wherein each of the photodetectors comprises a first surface and a second surface and a lens disposed on the first surface of the photodetector, the lens operable to focus light on a detector pixel.

5. The apparatus of claim 4, wherein the lens comprises a micro-electro-mechanical system (MEMS) lens.

6. The apparatus of claim 4, wherein the lens is disposed on the first surface of the photodetector.

7. The apparatus of claim 5, wherein the MEMS lens comprises a lens array, the lens array disposed on the photodetector array.

8. A method comprising:

reading a plurality of pulsed signals;

determining a position count based at least in part on the pulsed signals;

communicating the position count to a processor; and

providing a photodetector array operable to read the pulsed signals, wherein the photodetector array comprises;

at least two first photodetectors and at least two second photodetectors, the first and second photodetectors forming a first channel of the photodetector array, the first photodetectors linked together and the second photodetectors linked together, one of the first photodetectors adjacent to at least one of the second photodetectors; and

at least two third photodetectors and at least two fourth photodetectors, the third and fourth photodetectors forming a second channel of the photodetector array, the third photodetectors linked together and the fourth photodetectors being together, one of the third photodetectors adjacent to at least one of the fourth photodetectors, the second channel offset from and out of phase with the first channel.

9. A method comprising:

reading a plurality of pulsed signals;

determining a position count based at least in part on the pulsed signals;

communicating the position count to a processor; and

providing a photodetector array operable to read the pulsed signals, wherein the photodetector array comprises;

at least two first photodetectors and at least two second photodetectors, the first and second photodetectors forming a first channel of the photodetector array, the first photodetectors linked together and the second photodetectors linked together, one of the first photodetectors adjacent to at least one of the second photodetectors; and

at least two third photodetectors and at least two fourth photodetectors, the third and fourth photodetectors forming a second channel of the photodetector array, the third photodetectors linked together and the fourth photodetectors being together, one of the third photodetectors adjacent to at least one of the fourth photodetectors, the second channel offset from and approximately 30 degrees out of phase with the first channel.

10. A method comprising:

reading a plurality of pulsed signals;

determining a position count based at least in part on the pulsed signals;

communicating the position count to a processor; and

providing a photodetector array operable to read the pulsed signals, wherein the photodetector array comprises;

at least two first photodetectors and at least two second photodetectors, the first and second photodetectors forming a first channel of the photodetector array, the first photodetectors linked together and the second photodetectors linked together, one of the first photodetectors adjacent to at least one of the second photodetectors; and

at least two third photodetectors and at least two fourth photodetectors, the third and fourth photodetectors forming a second channel of the photodetector array, the third photodetectors linked together and the fourth photodetectors being together, one of the third photodetectors adjacent to at least one of the fourth photodetectors, the second channel offset from and out of phase with the first channel, wherein the first and second channels are disposed on a semiconductor integrated circuit chip.

11. A method comprising:

reading a plurality of pulsed signals;

determining a position count based at least in part on the pulsed signals;

communicating the position count to a processor; and

providing a photodetector array operable to read the pulsed signals, wherein the photodetector array comprises;

at least two first photodetectors and at least two second photodetectors, the first and second photodetectors forming a first channel of the photodetector array, the first photodetectors linked together and the second photodetectors linked together, one of the first photodetectors adjacent to at least one of the second photodetectors; and

at least two third photodetectors and at least two fourth photodetectors, the third and fourth photodetectors forming a second channel of the photodetector array, the third photodetectors linked together and the fourth photodetectors being together, one of the third photodetectors adjacent to at least one of the fourth photodetectors, the second channel offset from and out of phase with the first channel, wherein each of the photodetectors comprises a first surface and a second surface and a lens disposed on the first surface of the photodetector, the lens operable to focus light on a detector pixel.

12. A method comprising:

reading a plurality of pulsed signals;

determining a position count based at least in part on the pulsed signals;

communicating the position count to a processor; and

providing a photodetector array operable to read the pulsed signals, wherein the photodetector array comprises;

at least two first photodetectors and at least two second photodetectors, the first and second photodetectors forming a first channel of the photodetector array, the first photodetectors linked together and the second photodetectors linked together, one of the first photodetectors adjacent to at least one of the second photodetectors; and

at least two third photodetectors and at least two fourth photodetectors, the third and fourth photodetectors forming a second channel of the photodetector array, the third photodetectors linked together and the fourth photodetectors being together, one of the third photodetectors adjacent to at least one of the fourth photodetectors, the second channel offset from and out of phase with the first channel, wherein each of the photodetectors comprises a first surface and a second surface and a lens comprising a micro-electro-mechanical system (MEMS) lens disposed on the first surface of the photodetector, the lens operable to focus light on a detector pixel.

13. A method comprising:

reading a plurality of pulsed signals;

determining a position count based at least in part on the pulsed signals;

communicating the position count to a processor; and

providing a photodetector array operable to read the pulsed signals, wherein the photodetector array comprises;

at least two first photodetectors and at least two second photodetectors, the first and second photodeteetors forming a first channel of the photodetector array, the first photodetectors linked together and the second photodetectors linked together, one of the first photodetectors adjacent to at least one of the second photodetectors; and

at least two third photodetectors and at least two fourth photodetectors, the third and fourth photodetectors forming a second channel of the photodetector array, the third photodetectors linked together and the fourth photodetectors being together, one of the third photodetectors adjacent to at least one of the fourth photodetectors, the second channel offset from and out of phase with the first channel, wherein each of the photodetectors comprises a first surface and a second surface and a lens comprising a micro-electro-mechanical system (MEMS) lens array disposed on the photodetector array.